The invention relates to detecting an object within a defined area using a digital imaging device, such as a CCD camera.
It is known to use two infrared detectors aligned across a defined area to detect intrusion into the area. Such IR detectors are used, for example, for garage doors and installed at the sides of the door opening. One of the detectors, a IR source send an IR ray to a receiver, or IR sensor aligned with the IR source located across the door opening. However, the function of the IR detectors is limited to detecting an interruption of the IR ray, and the detectors need precise alignment, which provide certain difficulties during their installation. Also, both detectors need wiring in order to be electrically connected to a power source and to a control unit.
There is a need for a simple, inexpensive detection device which is easy to install and which is able to control intrusions in a defined area as well as to provide some other function such as determining the position of the barrier and the velocity of the barrier movement when used with a barrier movement operator.